The present disclosure relates to a region extraction processing apparatus, method, and program for extracting, from a lumen image which includes a hollow organ, a residue region in the hollow organ.
Recently, it has been practiced to extract a hollow organ, such as a large intestine, a small intestine, a stomach, from a three-dimensional image captured by a modality, such as a computed tomography (CT) system, and to use the three-dimensional image of the extracted hollow organ for image diagnosis.
For example, it is possible to create an image as if observing by an endoscope by CT imaging a large intestine with the air in the large intestine, and volume rendering the three-dimensional image captured by the CT imaging from inside the large intestine, and such image is called a virtual endoscopic image.
When generating the virtual endoscopic image, it is necessary to extract the large intestine from the three-dimensional image. It is also necessary to empty the inside of the large intestine before examination, but sometimes a residue may remain in the large intestine. The residue remaining in the virtual endoscopic image may hinder the observation of inside the large intestine.
Hence, the volume rendering may sometimes be performed by virtually generating a three-dimensional image without any residue by contrasting and imaging a residue in advance and eliminating the residue region by image processing after the CT imaging, and such processing is called as a digital cleansing. FIG. 10 shows an example of a virtual endoscopic image generated using a three-dimensional image before being subjected to the digital cleansing, while FIG. 11 shows an example of a virtual endoscopic image generated using a three-dimensional image after being subjected to the digital cleansing.
It is necessary to appropriately extract contrasted residue regions, as shown in FIG. 12, to perform the digital cleansing described above.
Japanese Unexamined Patent Publication No. 2006-198059 proposes a method that uses the fact that a boundary between the large intestine region (air region) and the residue region is horizontal and a region including the horizontal area is extracted as the residue region.